We frequent lifestyle clubs and have become friends with several great couples. However, not all couples are "play" quality. Okay, they are just not good-looking enough. Some of these friends believe that just because we are friends, that we will play with them.

We have sent out the "no thanks" vibe, but keep getting e-mails or casual hints and touches. We still want to remain friends to hang out and for sex networking sake, but not sex with them.

How do we remain friends with our club acquaintances, without hurting their feelings and without us having to "take one for the team"?

This is easier to do via e-mail correspondence if they're sending out the feelers online. It's always a bit awkward to do it in person.
If youíre open to pursuing friendships with others with whom you donít necessarily seek a physical attraction, hereís something you can work with: (and this is a great time to be cute and playful to soften the tone)
Would you guys be offended if we were total losers and said that we'd still love to hang out with you, since making friends is our main goals? But (and here's where we're losers) if a friendship with benefits is what you're exclusively looking to have with us, we certainly won't take it personally if you don't want to be friends any longer. But we would sure love to keep you around, because you're awesome company! Either way, we hope all of your dreams and fantasies come true, even if we're not part of them :)
P.S. We'll be at (insert venue here). Wanna hang out? We'll buy the first round!

This not only gives them the chance to take the rejection with their dignity intact, but it also proves you to be a classy person by responding to their probes despite your disinterest, and doing so in a classy manner. You do not need to provide reasons for your disinterest. That is your business, not theirs. If they write back asking for the reason, you can either choose to ignore it, or politely inform them that the reasons do not matter, only that you you still want to be buds.

Of course, amend this is needed to suit your own personalities and situation. This is a general idea of how to send rejection gracefully, while still offering your hand in friendship.